Final answer:
The statement that a categorical variable can always be measured using a nominal scale is true. Categorical variables fit perfectly into the nominal scale as they consist of categories without an inherent order.
Step-by-step explanation:
Regarding the statement "A categorical variable can always be measured using a nominal scale": this is true. A categorical variable involves placing items into categories and cannot be ordered or used in mathematical calculations, which is characteristic of nominal scale data. The nominal scale level is the most basic form of data categorization without a specific order. For instance, classifying people based on their hair color or assigning them to categories such as smoker and non-smoker is using a nominal scale because these categories have no inherent order.
On the other hand, variables that can be placed in a specific order are measured using the ordinal scale. If additional properties such as equal intervals or an absolute zero are present, the data might be considered interval or ratio scale level, respectively. But a categorical variable, by its very nature, fits the characteristics of the nominal scale perfectly.